ejb myclipse weblogic error

i'm using ejb 2 with myeclipse 9 and weblogic 9 . i'm learning java ee. was trying to use myeclipse.just testing with ejb2 have not yet started ejb3. getting following error when i run my client app.

error:
Exception in thread "main" javax.naming.NoInitialContextException: Need to specify class name in environment or system property, or as an applet parameter, or in an application resource file: java.naming.factory.initial
at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:645)
at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:247)
at javax.naming.InitialContext.getURLOrDefaultInitCtx(InitialContext.java:284)
at javax.naming.InitialContext.lookup(InitialContext.java:351)
at WishClient.main(WishClient.java:13)

1. can someone please tell me why i'm getting error. how should i resolve it.
2.when i'm using xdoclet to generate bean, home interface and xml files. it automatically generating jndi name. like this

public static final String COMP_NAME="java:comp/env/ejb/Wish";
public static final String JNDI_NAME="Wish";

so i commented them and used my own jndi name in weblogic -ejb-jar.xml. is it wrong to do that?. how come these variables have me declared in my home interface. why and how are they used. and i did not understand the structure --> java:comp/env/ejb/Wish .. what does it mean?. i'm a newbie . so please explain clearly.